Multitube heater for hot gas reciprocating engines



Dec. 16, 1952 A. A. DROS EI'AL 2,621,474

MULTITUBE HEATER FOR HOT GAS RECIPROCATING ENGINES Filed Jan. 16, 1951 as i INVENTORS ALBERT A. DROS ADRIAAN KOOPMANS ting 'e'ngir'res' 1 -z' r"r 1iznisinig {a heater'- I n V ybnd' the shatter hmbfs are-prowdedwith means arbiehlM-Iyatotheseengines whoseheatrs for--inereesing the-thermal transmission. Sjaiii series df bent- 'tubes. ineah'sma y be 'c qnstituted hy projections {such Ac iisi mg to the inventicsmsueh neb'ga's remy example, assfins. ninreeefih'g en ines are e'naeaeterizezd in at ina furth'er advantageou's embodimfint01th; the t;ub" e s 50f the heater surreund -a gpac 6r i invention/there n one of the long'er iimhsp the :n-cenmussmn gases are 'e a'u'sd {to ow 10- a lele eomb stien ea es fiqw :along s to tor space of the'--n- Dortionsin ajplum lity qf-grbupsof parallel eh n- ;g 'e, ithemoints of eotmeetibminto'thergeh-l netsywhien gmqps are 'prQYi'dedin series. *Itds ereto ggpa'qe Jointly surreundingthe-points f 7 thus ensured that ;the combustion gases Jane -acennecftfien into the-not ea -finder. in --additign,f "brought into intimate contact with the th bes, {argmufi of -stmilarylimbs oi rthe sex-he's of tub'eeh with the result that the thermal transxnjssiqh "is n 'bents "Such manner;that througha; portion even-more-improved, i n ,thi; enfgths,-.-sflbstantia1lyequaflgpassfigesfior The invention will now "be described more the :cohtbu'stion -:gases-%1re fermefl between one fugliy' 'hy ref ence Jto the aceqznpanyhxg ,drawlimb eifiptying into the hot eyiinder and itwo ing, wherein: aqiaeent "iimbsfi-emp'tyingjinte -the-regenem tor 'g. -1 is a verticafl -erqss-sectiona1jview qf a -.-s'ace.' diagrammatic representa; tion ,of :a he gee-1ean been feunfi that awhen aheater is -prociprocjatin'g engine wh'i chis constr-uqtei a2 :game a o embe -cit the engine; thergr6up of limbs along .i q 1 B e wee 'i mi of.

tioned substantially at right angles to the limbs 50 and spaced from both the lower wall l6 of casing l6 and the outer wall I of cylinder l. Bafile fins II are provided which extend alternately to said lower wall [6' and outer wall so that the combustion gases flow along the said portions 50 of said tubes in a number of groups of parallel channels with each group extending in a diiferent direction but in series with the others. The combustion gases finally leave the heater via a conduit l2.

It is evident that the fins may-be positioned in different ways. Thus, for example, it is possible that they may extend in the longitudinal direction of the tubes instead of transversely thereto.

In the embodiment above described, the tubes 5 are arranged concentrically about the combustion space H) of the engine, the combustion gases being supplied centrally and leaving the heater atits periphery. It is obvious, however, that the construction according to the invention is also applicable when the combustion gases are supplied at the periphery of the group of tubes and carried away centrally. Furthermore-it is not required that, as is the case in Figs. 1 and 2, the

limbs of the tubes are bent through aportion of their length in such manner that on a cross-sectionthrough this portion the cross-sections of the tubes-are located on the same circle. The limbs may be bent through this portion insuch manner'that a zig-zag pattern is formed. To ensure satisfactory operation of the heater, it is necessary, however, that the passages for the combustion gases between the limbs be substantially equal.

Having described a preferred form of the present invention and certain modifications thereof,

it will be evident that various changes therein may be made by persons skilled in the artwithout departing from the spirit and scope of the present invention. Consequently, it is to be understood that the foregoing description is to be considered illustrative of, rather than limitative'upon, the appended claims.

What we claim is: r

1. In a hot-gas engine having a hot cylinder and a regenerator, the improvement consisting of a heater for said engine, said heater comprisfing housing means enclosing a combustion space,

burner means for said combustion space, a series of bent tubes located adjacent the inner surface 'of said housing means, each of said bent tubes :compris'ing. two limbs, one of said. limbs-being connected-into the hot cylinder and the other 1imbbeing connected into said regenerator, the plurality of connections intosaid hot cylinder being. in a group surrounded by the group formed of the plurality of connections into the regenerator, eachof said .bent' tubes being so constructed and disposed with ,respect to one another that through a portion of the lengths thereof, sub- :stantially equal passages for the combustion gases ,jare' formed between a limb of one of said tubes 'connectedinto said hot cylinder and two of said other limbs of adjacent two tubes connected into said regeneratorspace. 2. In a hot-gas engine having a hot cylinder "and a regenerator, the improvement consisting of a heater for said engine, said heater compris- "ing housing means enclosing a combustion .space, burner means for said combustion space, a series of bent tubes located adjacent the inner surface of said housing means, each of said bent tubes comprising two limbs, one of said limbs being connected into the hot cylinder and the other limb being connected into said regenerator, each of said one limb being shorter in length than is said other limb, the plurality of connections into said hot cylinder beingin a group surrounded by the group formed of the plurality of'connections into the regenerator, each of said bent tubes being so constructed and disposed with respect to one another that through a portion of the lengths thereof, substantially equal passages for the combustion gases are formed between a limb of one of said tubes connected into said not cylinder and two of said other limbs of adjacent two tubes connected into said regenerator space.

3. In a hot-gas engine having a hot cylinder and a regenerator, the improvement consisting of a heater for said engine, said heater comprising housing means enclosing a combustion space, burner means forsaid combustion space, a series of bent tubes located adjacent the inner surface of said housing means, each of said bent tubes comprising two limbs, one of said limbs being connected into the hot cylinder and the other limb being connected into said regenerator, each of said one limb being shorter in length than each of said other limb, the plurality of connections into said hot cylinder being in a, group surrounded by the group formed of the plurality of connections into the regenerator, each- 0f said bent tubes being so constructed and disposed with respect to one another that through a'portion of the lengths-thereof, substantially equal passages for the combustion gases are formed between a limb of one of said tubes connected into said hot'cylinder and two of said other limbs of adjacent two tubes connected into said-regenerator space, and each of the portions of*said longer limbs projecting beyond-said shorter limbs provided with means to increase the thermal transmission thereto.

4. In a. hot-gas engine having a hot cylinder and a regenerator, the improvement consisting of a heater for said-engine, saidheater comprising housing means enclosing a combustion space, burner means for said combustion space, a series of bent tubes located-adjacent the inner surface of-said housing means, each of said bent tubes comprising two limbs, one of said. limbs being connected into .the hot cylinder and the other limb being connected into-said regenerator, each of said one limb being shorter in length than is said other limb, the plurality of connections into said hot cylinder being in a groupsurrounded by the group formed of the plurality of connections into the regenerator, each of said bent tubes being so constructed and disposed with respect to one another that through a portion of the lengths thereof, substantially equal passages for the combustion gases are formed between a limb of a heater for said engine, said heater comprising'housing means enclosing a combustion space, burner means for said combustion space, a series of bent tubes located adjacent the inner surface of said housing means, each of said bent tubes comprising two limbs, one of said limbs being connected into the hot cylinder and the other limb being connected into said regenerator. each of said one limb being shorter in length than is said other limb, the plurality of connections into said hot cylinder being in a group surrounded by the group formed of the plurality of connections into the regenerator, each of said bent tubes being so constructed and disposed with respect to one another that through a portion of the lengths thereof, substantially equal passages for the combustion gases are formed between a, limb of one of said tubes connected into said hot cylinder and two of said other limbs of adjacent two tubes connected into said regenerator space, each of the portions of said longer limbs projecting beyond said shorter limb being provided with a plurality of transverse fins for increasing the thermal transmission thereto and bafile means associated with said limb portions for directing the REFERENCES CITED The'following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 289,484 Woodbury et a1 Dec. 4, 1883 289,485 Woodbury et al Dec. 4, 1883 324,062 Woodbury et al Aug. 11, 1885 327,748 Woodbury et a1 Oct. 6, 1885 331,361 Woodbury et a1 Dec. 1, 1885 

